“Dog cemetery, Hartsdale,” New York, between ca. 1910 and ca. 1915, by Bain News Service, via Library of Congress Prints and Photographs Division.
The Hartsdale Pet Cemetery is the oldest operating pet cemetery in the world and the only one listed on the National Register of Historic Places, according to its website. It was founded in 1896, in the apple orchard of a New York City veterinarian.
Today, it holds the graves of over 80,000 animals, including the pets of Diana Ross, Irene Castle, and Mariah Carey.